If you do get it checked out by the dealership, please post back with what they tell you (if anything).

I haven't done much driving since the 3.5.1 and A4 updates, just a few minutes back and forth from work, but I'll let you know if I see a lag, myself. As was noted before, the only way to calibrate GPS is to take it to the dealership, which is a bit annoying.

My '06 Mazda3 had a pretty simple calibration feature I ended up using a couple of times over the six or so years I had it.

If this keeps up I'll make a note of it and check with my dealership, and I'll let you know. It's something I'd probably hold off until my next scheduled maintenance.

Interesting to hear that you are having problems with GPS even parking in the open. I'd assumed it was because I was out of satellite range. Satellite-based devices don't work in the garage on any car I've been in, so that was just an bad assumption on my part. Without GPS, it looks like the navi just relies on speed and turns, so throw in a few levels of a parking garage and I'm about a 1/4 mile off facing the opposite direction most of the time. And, add to that the time it takes for the car to pick up a GPS signal and things start to get pretty comical.

Yesterday I was driving alongside a road for about a mile after coming out of the garage. I thought the navi would have rounded off to the nearest road--there were no side roads to get confused with--but nope, I was just driving in the ditch, I guess.